Open-hearth furnace



F. B. McKuNE OPEN HEARTH FURNACE METALLURGIGAL FURNACE `original Filedoct. 27. 1919 4 Sheets-Sheet 1 www.

Re, 16,837 F. B. MeKuNE l oPN HEARTH FURNAGE AMETALLURGXgm. FURNAcE lOriginal Filed Oct. 27. 1919 4 Sheets-Sheet 4 wx. bh,

Reiue'd Dec. 27, 1927.

UNITED- STATES Re.16,s37

PATENT orifice'.

FRANK B. MQKUNE, OF HAMILTON, ONTARIO, CANADA, ASSIGNOR, BY MESNEASSIGN- MENTS, TO OPEN HEARTH COMBUSTION COMPANY, OF CHICAGO, ILLINOIS,A COB- PORATION OF DELAWARE.

Original No. 1,339,855, dated May 11, 1920, Serial No. 333,756, filedOctober 27, 1919. Application for OPEN-HEART?! FURNACE.

reissue tiled May 5, 1922. Serial No. 558,754.

This invention, which relates generally, to improvements in` open hearthfurnaces, more Aparticularly has for .its object to provide certainimproved structural arrangements in furnaces of the character referredto, especially adapted for the economical burning of gases, a moreuniform distribution thereof and for lengthening the life of the furnaceand the check-eil work that constitutes a part thereof.

Another and essential object of my invention is to provide in an openhearth furnace, certain improved features adapted for Aincreasing tlierapid melting of the heat and which give absolute control of the flamein such furnace, with a material productive increase over the methodgenerally utilized for heating nieta-l in open hearth furnaces by meansof the combustion of gases.

With other objects in viciv, my invention, in its subordinate features,embodies certain improvements in the damper rigging 'that controls theair induction and eduction and in such manner that little or -no gas islost, when reversing the furnace, and very little dirt carried downthrough the regenerators,`

communicate with the main air passages due to a perfect combustion ofthe gases.

In setting forth the improved details of construction of my open hearthfurnace, the

purpose otk-my invention will-be best under-v stood by referring to theaccompanying drawings which illust-rate a preferred form of myinvention, it being premised, however, that various changes in thedetails or modifcations of the cooperative arrangement of .the partsshown may be readily made without departing from the spirit and thescope ports, one at each end, into which the gases are delivered in any7suitable manner, preferably by tunnels 2 2.` which extend transverselyinto the opposite sides of .the

furnace Walls` and which communicate, through the Jet outlets 20-20,with the gas ports 1 1 and which connect, at their outer ends, With-thesupply branches 30-30 that Join with the main laterals or gas pipes31-31, which in turn, connect with the main supply pipes 3 in the mannerclearly shown 1n Figures 1 and 3 of thedrawings.

The gas ports 1-.1, before referred to,

supplemental air passage 4 4 is located at' each side of the gas ports 1-1 and their air passages 10-10, it being understood that of myinvention as defined in the appended the arrangement of the gas, themain air claims. y ports, the supplemental air ports, and the 40 In thedrawingscontrol mechanism,presently explained, are

Figure 1 is a horizontal section of-an open hearth furnace embodying myinvention, the damper operating mechanism at both ends being shown inplan view, the damper at one end (the. inlet) being shown as whollyclosed and the damper at'the other end (the outlet) being shown aswholly opened;

Figure 2 is a vertical longitudinal section' alike, so thatwhenreversing'the ports'at one end, serve .as inlets and ports at theopposite ends as the outlets and viceversa.

In the complete assemblage of the parts,` comprised in my constructionof open hearth furnace, is included hydraulic damper rigging devices,which, per se, constitute an essential feature of my invention.

As is best shown in Figures 1 and 2, the damper rigging consists ofdamper doo-rs .7-7, one for each supplemental air passage 4--4 and thesaid doors are slidably mount fed between pipes 8 8 that extend throughy -ioo .openings 9 9 in the end Walls of the furas indicated at the leftof Figure 2.

Each damper or cut ofi' door 7 is` provided fwithan out-wardly extendedmember 70 and each of the members 70 has a slotway 71 into which isreceived the lower.end of a y lever 12 secured at the upper end on ashaft 13 vthat is journaled in suitable bearing brackets 14-14 attachedto and projected from the end walls of the furnace.

rI he shaft 13, midway its length, has a crank member hereinafter termedthe cylinderlever 15, with whichjoins a vertically reciprocable shaft 16 that connects with the pistons of a pair of hydraulic cylinders 17-17,suitably mounted over the outer face of eachend wall and which includethe alternately operating intake and outletA pipes 18, which, inpractice, are connected up in any well known manner with a fluid supplyfor actuating the cylinder pistons for shifting the dempers 7-7, atpredetermined times, for reversing the furnace.

While I have specifically mentioned hydraulic cylinders for actuatingthe devices thatshift the dempers to theV wholly or part'- ly open orclosed positions it is to be understood that the operation of thedampers or doors 4 4 can be done by hydraulic steam, electricity orcompressed air with the control of the same absolutely under the'furnace operator.

40 designate cooling pipes that enter through the sides of the furnaceadj acentthe gas tunnels. y

From the foregoing description taken in connection with the drawings,the complete arrangement, the manner of using and the advantages of myinvention will be readily apparent to -those familiar with the operationor use of 'furnaces of the type rel ferred to.

It is to be understoodthat While the entire `air can be directed throughthe passages to the gas ports 1 1, yet incase it is desired that aportion of `the air go over the top,

it is only a matter of opening the dampersI at the inlet end to anydesired degree, depending upon the amount of air that may be desired forgoing over .the top of the furnace, it being readily apparent byreferring d' to the drawings that, whenthe dampers in the supplementalair passages4-4 are open, the air continues up along the passagesoverthe arched top through which the gas ports `pass and are dischargeddirectly under the top of the hearth.

To ive the necessary laea that may be desire, .the dempers at theoutgoing end of the'furnace are pulled opentheir entire length, asshown. l By controlling the air and gas supply 1n the manner stated, itincreases the yield of the heat 'at least two per cent, due' to gettingthe air' thoroughly mixed with the fore heating the metal. f-

lVith the dampers,. ranged as shown andV described. it is possible toeffectively control the velocity'of air and gas entering the furnace andalso to burn gases bebefore referred to, ar-

through one single port, vany gas, and at the v nace, there is no freeair-*going into the furnace except through the passages l.

The Working of any-gas burning furnace is improved, since there is noloss of gas in reversing, which is customaryon areverberating furnace.

In my furnace, the gas enters the port and is completely cut off beforereversing the furnace.

The 'fiow of gases in my furnace can be",

changed'lyvithout vstopping the furnace and the cost of repairs is verymuch less than is usual iii-.other types of like furnaces, due.

to the perfect control an'dcompletecombus- I tion ofthe ases. s

Further, 1n my construction of furnace,

time. My improvements to anyof the conventional types of furnaces and,in building new furnaces, it would be only necessary tohave tworegenerators instead of four. y

Furthermore, in the practical use of my i invention no gases are lost inreversing the may be readily Aapplied -no it is possible to work in anycombination ofliquid fuel or any two gases at the same furnace and alsovery little dirt carried down through the regenerators, due to theperfect combustion obtained from the gases.

Another and important advantage in the use of damper controls arrangedas shown and described, is, that since vit is necessary to be able toconcentrate the gas and air t-l`rough the one port on'the incoming endofthe furnace, this can be only effectively done by'the use of my dempersand valves.

If this were done without the use of valves a arrangedl as in myconstruction, it would be -impossiblf to get the velocity on the gas andair, which is necessary to get the combustion and effects brought aboutby the proper manipulationof my damper device.

By having the dampers so tha't one can open them on the outgoing end otthe fura gas port at each of nace, by doing so the full arca of thedampers and thc stack, otherwise the draftv on the furnace would vbechecked.

In the use of my special arrangement of valve and damper mechanism,itbrings about a great saving, `when reversing the `valves as no gaspasses through the reversing valves whatever.

The advantage of this feature of my invention will be apparent, when itis understood that 15% of the `gas required to run the furnace is lostin the reversing of the furnace.

I claim: A

1. An open hearth furnace having a hearth, a gas port at each of theopposite ends, an air channel that connects with each gas port, asupplemental air channel .at each end that discharges into the top ofthe furnace, damper controls for opening' and closing the saidsupplemental air channels and means for supplying gas to t-he gas ports;

2. An open hearth furnace having a hearth, a main air port and asupplemental air eing arranged to discharge over the bed or hearth, thesupplemental air port being a1;- ranged over the closed top of the mainair ort and to discharge along the to of the urnace, means for supplyinggas alternately to the main air ports at either end adjacent theirdischarges into the furnace, a damper in each of the supplemental airports, and means for opening and closing said dampers for reversing thedirection of the air and gas suppl to the furnace.

3. An open hearth fi'irnace having a hearth, the opposite ends, an airchannelthat connects with each gas port, sup lemental air channels ateach end that disc arge into the top of the furnace, damper controls forgpening and closing the said, supplemental alr channels and means forsupplying gas to the as ports.-

In an open heart furnace in which is included a main air port thatdischarges onto the hearth, a -gas supplying port in connection with thesaid main air port adjacent the discharge end of the said air. port, apair of supplemental air ports that extend vertically,l one at each sideof the main air port, and. which discharges a'long the crown of thefurnace, a damper in each supplemental air port for opening and closingthe said port and means for adjusting the said dampers.

5. In an open hearth furnace in which is vonto the hearth, a gassupplying portinv connection with the said main air port adjacent thedischarge end of the said air port, a pair of supplemental air portsthat extend vertically, one at cach side of the main air port, and whichdischarges alongthe crown of the furnace, a damper in each supplementalair port for opening and closing the said port and means for adjuetingthe said dampcrs, said means including a rotative shaft, a lever foreach damper at.- tached to the shaft and means for imparting reverserotation' to the shaft for adjusting the said dampers to open and close-the port.

6. In an open hearth furnace 1n which is vertically,.one at each side ofthe main air l port, and which discharges along the crown of thefurnace. a damper in. cach supplemental air port for opening and closingthe said port and means for adjust-ing the said dampers, the said lastmentioned ,means comprising a rigging that consists of a rock shaft,link connections that join the dampers to the shaft and means forrocking the shaft. port at each end thereof, the main air port 7. In anopen hearth furnace, in which is included a main air port thatdischarges onto the hearth, a gas tunnel in communication with the saidair port, a gas supply in communication with the tunnel, a supplementalair port that passes adjacent and 'is adapted for cooling the main airport, a guideway thatextends horizontally across the supple- -mental airport, a damper slidably mounted in the said -guideway and adapted foropenlng and closing the supplemental air port,

-the said air port being arranged for conveylng air over the crown ofthe furnace for cooling and for intermixing with the air and gas fromthe main air port, means for sli-dably actuating the damper, the' saidmeans including a rock shaft, a lever arm that connects the shaft andthe damper, and means for rocking the shaft,'the said means comprising apair of hydraulic cylinders, a rod connecting the working pistons of thetwo cylinders, and a connection that joir the said rod and the shaft forrocking the said shaft in reverse directions, as the piston rod isreeiprocated at times.

8. In a reversible regenerative furnace, air

and gas ports and passages in each end lao into a flow of relativelyhigh velocity at its entrance into'the furnace chamber.

9. In a reversible regenerative furnace,

air and gas ports and passages in each end thereof, and movable meansin' association with certain of said ports andpassages for concentratingvthe'incoming air into a ilow of relatively lii h velocity, said meansupon the outgoing en further serving to permit the diffusion oftheoutgoing gases in a flow of relatively low velocity.-

10. In 4a reversible regenerative furnace, ports and passages in eachend thereof for the introduction of air and fuel and the egress of`exhaust gases, and means fol.'-

changing the combined area of the ports and passages whereby the exhaustgases from the furnace may be discharged at a lower velocity than thatof the incoming aii and fuel.

11. In-,a reversible regenerative furnace, main ports and auxiliary.ports in the ends of the furnace, and means associated` with the auxiliaIports adapted to control the 'area availa le for the passagel of'gases,l

vthrough saidports whereby the velocity of outflow of the products of'combustion throughthe main and auxiliary ports is rendered'diferent fromthe velocity of the incomino air and fuel through said ports'. 12. In areversible regenerative furnace,

movable'ineans in certain of the furnace ports' and lpassages'providingl Vdiierential control vof the velocity of the inowing mixthewith gas passagses,

ture of air and fuel through concentrating the flow through a relativelyrestricted area, l

and of the velocity of the outflowing products of combustion throughselectively determined enlargement of the area" through which the gasesleave'the furnace. Y

13. In a reversible regenerative furnace, air and fuel ports andpassages in each end thereof, certain of said air passages joining aspassages and being closed'oi from urnace chamber up to'their junctionand-movable means in said furnace en -adapted to' concentrate theincomin air and fuelinto a flow of relatively high velocity atlthepointof entrance into theffuha'io'chalnber.

14. In arevrsible regenerative furnace, fuel and ports at the-'ends ofthe furnace chamber, said 'ports constituting -common means for'entranceand egress of gases to and from the furnace chamber, and movable saidvmeans for, restricting. the eliective area of said- `-Korte,wherebvthefuel and air entering t e furnace chamber may-be caused topass through a restricted area of said ports at 'a relatively highvelocity; and the roducts of combustion passing from said c amber may becaused to pass throu h an en- .larged area of said ports I atgrelatively low velocity.

i Signed at Hamilton, Ontario, this 21st day OfApril, 1922. y 1

- I *"-FRANK B MCKUNE.

